Tuesday, March 24, 2020

Tuesday Tip - Ground Goop FAIL & recover....

During my recent scenery blitz, I've been using something I first saw on an Alan Keller video on Lou Sassi's layout: "Ground Goop"

The idea is to have something you can apply to the scenery form that will provide additional undulation to the scenery and, perhaps most importantly, provide something thicker than paint to stick things into. Some even use this directly on the scenic form instead of paint, thereby eliminating a step in the scenery process.

It's particularly effective at making little landforms like small bumps/hills, eroding hillsides, and riverbanks. You can also push your structures down into it before it hardens, thereby eliminating that "sitting on top of the scenery" look.

The original formula called for 1 part each of ground color paint, vermiculite, and Celluclay, 1/2 part white glue, and a jigger of Lysol if you want to keep it from going bad in storage. I've seen other formulas, including one that just mixes Sculptamold with ground color paint (I think Mike Confalone uses this recipe).

My formula is a bit different:

  • 2 parts Sculptamold
  • 1 part paint
  • 1 part glue
  • Just enough water to make it peanut butter/oatmeal consistency.

I eliminated the vermiculite early on since it looked too shiny and coarse to me.

Things worked pretty well, though I always had a problem with the mix being a bit lumpy. So I decided to check out the Sculptamold mixing instructions. Apparently, I'd been doing it wrong. Instead of dumping in the Sculptamold first and then adding the liquids, you're supposed to put in the water first, then add the Sculptamold in slowly, mixing it in as you go.

Well, after doing that and adding the paint and glue, it was MUCH too watery. So I just kept adding more Sculptamold. And more. Until it was that oatmeal/peanut butter consistency.

By then, it was time to retire for the evening.

This is what I had the next morning:

Yup - hard as a rock!  Yes, I sealed it. No, I couldn't salvage it.

Thinking I'd followed the directions wrong somehow, I tried again. UGH! Same result - but this time I caught it before it had totally hardened, added some water, and with a LOT of stirring effort was able to salvage it.

What's going on??

As with a lot of questions lately, I get the quickest response from The Valley Local FB Group. Apparently, the main reason the goop reacted so differently this time is that Sculptamold has hydrocal in it and adding it to water (rather than vice-versa) causes a chemical reaction which solidifies it much more quickly. At least that's what I remember being the gist of the responses.

Suffice it to say, I've gone back to my original process: 2 parts Sculptamold in a bowl, add 1 part paint, add 1 part glue, mix thoroughly, then add just enough water to make it like thick oatmeal. I may try adding less glue (not really sure I need to use that much).

Oh - and I just mix it more thoroughly (and dip my trowel in water occasionally) to smooth it out.

Here's how it looks when troweled on:

The change in color is the result of, um, a change in color. I decided to try and lighten things up a bit. Don't worry - I'll blend it in.

For the front of the layout, I protect the fascia (and the floor), by adding a dam/barrier of masking tape.

Then just trowel it on and smooth it. The thinner the application, the quicker it'll dry. But with this batch I've troweled on as much as 1" thick and it was dry within 24 hrs (but that's during winter - it may take longer during a humid summer).

Another view - all smoothed out.
While the goop is still wet, I sprinkle on my base ground cover - a mixture of different colors of "fine" ground foam. Between the paint and the glue, there's a lot to stick to. But I still mist the ground cover with 70% isopropyl alcohol (IPA) as a wetting agent, then apply diluted white glue to fix it all in place. For now, I'm applying the glue with either an old saline solution bottle or a pipette - but I'm trying to find a way to mist on the glue as well so I can cover a wider area more quickly.

I think most folks paint right over the scenery shell and either add their base ground cover to the wet paint, or brush on glue after the paint has dried. That may work well with foam-based scenery, but I'm using the cardboard strip/plaster cloth scenery base and want to cover the "lattice" look. I could try doing the lattice in a tighter "weave" - but I still like creating a thicker layer for adding trees and such.

Let me know in the comments your thoughts on using ground goop - and if a different method works for you, I hope you'll let us know!


  1. Chris, from experience over a few years, I found out you can not only get rid of vermiculite, but also of glue. Latex paint is a powerful glue already. I had to tear down scenery made of that mix and it is almost impossible to rip.

    1. Ah! Ok - thanks Matthieu! Sounds like you & Mike Confalone are in the same place - just a mix of paint and Sculptamold (and I assume just enough water to make it spreadable). I'll definitely try that next time - especially since I'm now running low on glue! Thanks for stopping by and taking the time to leave a comment - cheers!